Touch Screen Device and Methods Thereof Configured for a Plurality of Resolutions

ABSTRACT

Disclosed is a touch screen and a method of touch screen having a first plurality of sensor segments coupled to first scan lines and a second plurality of sensor segments being subsections of one of the first plurality of sensor segments, the second plurality of sensor segments including second scan lines that are bundled by a multiplexer configured to aggregate output of the second plurality of sensor segments into a single transmission channel. The individual output of the multiplexed sensor segments subsections can be either combined into a single signal for processing during a normal scan, or their individual output can be processed individually for higher resolution. Using two scans, the first a normal scan, and the second a higher resolution scan, the disclosed touch screen and methods zoom in on the proximity of the touched area and scans with a higher resolution the proximity only where it is needed.

FIELD

Disclosed is a touch screen and a method of touch screen having a firstplurality of sensor segments coupled to first scan lines and a secondplurality of sensor segments being subsections of one of the firstplurality of sensor segments, the second plurality of sensor segmentsincluding second scan lines that are bundled by a multiplexer configuredto aggregate output of the second plurality of sensor segments into asingle transmission channel.

BACKGROUND

Many types of electronic devices incorporate touch screens, such ascapacitive and resistive touch screens. Touch screens are utilized toprovide input in response to menus, and to receive content such asindicia formed by a user's finger trace, or a stylus. Capacitive touchscreens are digital, their accuracy being dependent upon theirresolution.

A capacitive touch screen utilizes sensor segments, each having atransparent electrode to sense touch. A sensor segment can have adiamond shape. A transparent electrode of the sensor segment is coupledto a scan line in the horizontal direction, and a scan line in thevertical direction. Typically, the scan lines are scanned at 60 Hertz(Hz) or higher frequency. The scan speed can be matched to follow atypical finger movement. Thus an entire touch screen can be scanned atsuch a scan rate in order trace the finger movement. If the scan ratewere any faster, power efficiency and touch signal strength would becompromised with no added benefit.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying figures, where like reference numerals refer toidentical or functionally similar elements throughout the separate viewsand which together with the detailed description below are incorporatedin and form part of the specification, serve to further illustratevarious embodiments and to explain various principles and advantages allin accordance with the present invention.

FIG. 1 illustrates how a straight diagonal line is recognized by a touchscreen device with typical resolution;

FIGS. 2A and 2B depict an embodiment of a single diamond shaped sensorsegment;

FIG. 3 depicts an embodiment of subsections of a sensor segment as afour-by-four matrix of sensor segment subsections;

FIG. 4 depicts an embodiment of a touch screen that includes sixteentraditional sensor segments, identified by a vertical gridlinescollectively illustrated demarking columns 1-4, and a horizontalgridlines collectively illustrated demarking rows 1-4;

FIG. 5 depicts several different embodiments of a touch screen 530 andportions of circuit components; and

FIG. 6 is a flow chart illustrating a plurality of embodiments ofmethods of disclosed touch screens.

DETAILED DESCRIPTION

Increasing touch screen resolution can be accomplished by introducingmore sensor segments. For example, two sensor segments could replace asingle sensor segment. However, by introducing additional sensorsegments and their respective transmission channels, the sensitivity ofthe touch screen would be reduced because the scan rate would remain thesame, but the time available to scan each sensor segment would bedivided in half reducing the signal strength and making it noise prone.Additionally, with twice the transmission channels, the complexity ofthe device would be substantially increased. It is preferable to keepthe number of transmission channels used to a minimum.

Poor touch screen resolution is particularly problematic for handwritingrecognition, especially with Chinese characters. As mentioned, a touchscreen's accuracy is dependent upon its resolution, a typical sensorsegment having the dimensions of 5 to 8 in periodicity and 25 to 70millimeters squared (mm²). With such a resolution, were a user to draw,for example, a line diagonally across a touch screen, a straightdiagonal line would be recognized as a bumpy line.

FIG. 1 illustrates how a straight diagonal line is recognized by a touchscreen device 100 with typical resolution. A plurality of diamond shapedsensor segments 102 may be scanned by the sensor grid 104. The dottedline 112 represents an actual finger path, diagonal across the touchscreen device 100. When the user touches at the edge of a, for example,sensor segment 110, but not overlapping any other sensor segment, thecontroller (shown below) has no way of determining that the touchoccurred anywhere other than the center of the sensor segment 110. Thebumpy line 108 represents the sensed finger path. As mentioned,handwriting recognition applications could find such a bumpy line 108difficult or impossible to interpret.

Disclosed is a touch screen and a method of touch screen having a firstplurality of sensor segments coupled to first scan lines (transmissionchannels) and a second plurality of sensor segments being subsections ofone of the first plurality of sensor segments, the second plurality ofsensor segments including second scan lines that are bundled by amultiplexer configured to aggregate output of the second plurality ofsensor segments into a single transmission channel. In this way, aplurality of sensor segments subsections may replace a sensor segmenthaving traditional dimensions. The replacement sensor segmentssubsections have scan lines that are multiplexed so that theirindividual output can be either combined into a single signal forprocessing during a normal scan, or their individual output can beprocessed individually as will be discussed below. So in a way, thedisclosed touch screen device is configured with at least tworesolutions. The disclosed touch screen has both a traditionalresolution, and a higher resolution.

The scanning process can be broken down into two processes. A disclosedmethod includes first scanning scan lines (transmission channels) of aplurality of multiplexers, each of which combine the signals of aplurality of multiplexed sensor segments during a normal scan todetermine the proximity of input to the touch screen. That is, the firstscan can deliver output to the controller to determine if a touch hasoccurred and its proximity with traditional resolution. When theproximity of touch input is detected, a second scan is processed withinthe proximity of the detected touch, but this time, the individualsignals of the sensor segment subsections are not combined to form asingle output, they are instead individually processed, providing a scanof higher resolution.

To increase the resolution in accordance with the disclosed touch screenand methods thereof, in one embodiment, a traditional sensor segment maybe divided into sixteen subsections, forming a four-by-four matrix,having four channels in the horizontal direction and four channels inthe vertical direction. The first scan may only detect that touch hasoccurred somewhere within the four-by-four matrix of sensor segmentsubsections. In the second scan, the sensor segment subsections of thefour-by-four matrix of are individually processed to determine which ofthe subsections received the touch input. The effect of the second scancan be characterized as selectively increasing the resolution of theoverall touch screen. Put another way, using two scans, the first anormal scan, and the second a higher resolution scan, the disclosedtouch screen and methods zoom in on the touched area and scans with ahigher resolution only where it is needed. In such an embodiment, thetime it takes to scan at the disclosed higher resolution is only twiceas long, whereas adding normal scan channels, for example, twenty-fournormal scan channels could impact the scan rate at least that much.Beneficially, many disadvantages of increasing the resolution may beavoided by the disclosed touch screen and disclosed methods.

The instant disclosure is provided to explain in an enabling fashion thebest modes of making and using various embodiments in accordance withthe present invention. The disclosure is further offered to enhance anunderstanding and appreciation for the invention principles andadvantages thereof, rather than to limit in any manner the invention.While the preferred embodiments of the invention are illustrated anddescribed here, it is clear that the invention is not so limited.Numerous modifications, changes, variations, substitutions, andequivalents will occur to those skilled in the art having the benefit ofthis disclosure without departing from the spirit and scope of thepresent invention as defined by the following claims. It is understoodthat the use of relational terms, if any, such as first and second, upand down, and the like are used solely to distinguish one from anotherentity or action without necessarily requiring or implying any actualsuch relationship or order between such entities or actions.

At least some inventive functionality and inventive principles may beimplemented with or in software programs or instructions and integratedcircuits (ICs) such as application specific ICs. In the interest ofbrevity and minimization of any risk of obscuring the principles andconcepts according to the present invention, discussion of such softwareand ICs, if any, is limited to the essentials with respect to theprinciples and concepts within the preferred embodiments.

FIGS. 2A and 2B depicts an embodiment of a single diamond shaped sensorsegment. A transparent electrode of the sensor segment 220 is coupled toa scan lines (transmission channel) 222 and 224 in the verticaldirection. Another transparent electrode of the sensor segment 226 iscoupled to the scan lines (transmission channel) 228 and 230 in thehorizontal direction. A sensor segment can be of any appropriate shape.A traditional sensor segment for a utility such as a touch screen of amobile communication device has dimensions of 58 in millimeter in theperiodicity. It is understood that any touch screen having sensorsegments of any dimensions and/or shape in the disclosed configurationand that operates in the disclosed manner is within the scope of thisdiscussion.

FIG. 3 depicts an embodiment of subsections of a sensor segment as afour-by-four matrix of sensor segment subsections. Depicted are sixteensubsections, four in the horizontal direction 326 and four in thevertical direction 328. As with the single sensor segment 220 and 226(see FIG. 2), the sixteen subsections are coupled to scan lines, 222 and224, in the horizontal direction and to scan lines 228 and 230 in thevertical direction. It is understood that any number of subsections arewithin the scope of this discussion. For example, were there one hundredsubsections, the resolution may enable writing recognition from input ofa stylus well. More subsections can provide higher resolution. In anembodiment having sixteen subsections, the resolution can be improvedsixteen fold. Moreover, as discussed below, sensor segment subsectionswithin sensor segment subsections, multiplexed in layers, may providevarying degrees of resolution, which may be beneficial for certainapplications.

FIG. 4 depicts an embodiment of a touch screen 430 that includes sixteentraditional sensor segments, identified by a vertical gridlines 432collectively illustrated demarking columns 1-4, and a horizontalgridlines 434 collectively illustrated demarking rows 1-4. Each of therow or column is numerically identified by its position. For example,(1, 1) is at the lower most left hand corner of the touch screen, wherethe first number of (1, 1) represent the horizontal (row) FIG. 4 furtherdepicts that the subsections of the sensor segments identified by agridlines 436 collectively illustrated demarking rows 1-16 and agridlines 438 collectively illustrated demarking columns 1-16. Ofcourse, rows 1-16 have a finer resolution as rows 1-4 as do columns 1-16have a finer resolution than columns 1-16. In traditional grid modehaving a lower resolution, the detected touch 440 is at the (4, 3)intersection. The same touch can be resolved to (3, 2) of thesubsections of the (4, 3) quadrant. In the higher resolution, the sensorsegment subsection touch that is identified by grids 436 and 438, thefinal touch position is (11, 14).

FIG. 5 depicts several different embodiments of a touch screen 530 andportions of circuit components. Touch screen 530 is similar to touchscreen 430 depicted in FIG. 4, that would include sixteen traditionalsensor segments, each traditional sensor segment including a pluralityof subsections, in the example of FIG. 5, sixteen subsections pertraditional sensor segment form four-by-four matrices of sensor segmentsubsections. A detected touch 540 is similarly depicted in the (11, 14)position. As mentioned above, it is understood that any number ofsubsections is within the scope of this discussion.

In the embodiment illustrated by FIG. 5, touch screen 530 includessixteen scan lines in the horizontal direction and sixteen scan lines inthe vertical direction. A scan line from each of the sensor segmentsubsections is coupled to a multiplexer. That is, in the verticaldirection four sensor segment subsection scan lines are coupled to eachmultiplexer 550, 552, 554 and 556. In the horizontal direction four scanlines are coupled to each multiplexer 560, 562, 564 and 566. Themultiplexers 550, 552, 554 and 556 in the vertical direction 546 receivecolumn signals. The multiplexers 560, 562, 564 and 566 in the horizontaldirection 544 receive row signals.

As mentioned, touch screen 530 includes sixteen scan lines in thehorizontal direction 544 grouped into groups of four scan lines so thattheir signals can be combined by a multiplexers 560, 562, 564 and 566.For simplicity of illustration, multiplexers 562 and 564 having scan(transmission channels or drive) lines 563 and 565 that include arrowsto indicate their circuitry (not shown) coupling them to the controller580. In more detail FIG. 5 shows that multiplexer 566 can receive fourscan lines 568-A, 568-B, 568-C and 568-D that can detect touch 540 andthe multiplexer 554 has scan lines 580-A, 580-B, 580-C and 580-D so thatthey can combine their signals for a single transmission (drive or scan)line 572 and 555, respectively. In one example, when touch is detected540 at the lower resolution (4, 3) (see FIG. 4) by one of thesubsections having one of the lines 568-A, 568-B, 568-C and 568-Dcombined by multiplexer 566 and the lines 580-A, 580-B, 580-C and 580-Dcombined by multiplexer 554, the switch 576 in communication with line572 and corresponding switch for the multiplexer 555 (not shown) and thecontroller 580 is closed. Also illustrated in detail is that multiplexer560 receives scan lines 570-A, 570-B, 570-C and 570-D so that theirsignals can be combined for a single transmission channel 574. Theswitch 578 is depicted as open as no touch input is depicted in thatregion of the touch screen 530.

As discussed above, the scanning process can be broken down into two ormore processes. A disclosed method includes first scanning scan lines ofthe plurality of sensor segments in both the horizontal direction 544and in the vertical direction 542 to determine input 540 to the touchscreen 530 at a particular sensor segment (4, 3). Since the scan linesof the sixteen four-by-four matrices of sensor segment subsections aremultiplexed, their individual signals of some or all of the four-by-fourmatrices are combined to form a single output, so the first scan acrossthe entire touch screen is a normal scan. In the depicted touch screenof FIG. 5, the lower resolution scan would involve four row scans andfour column scans.

The second part of the process is scanning the scan lines 568-A, 568-B,568-C and 568-D for vertical position and 580-A, 580-B, 580-C and 580-Dfor horizontal position, individually when input to the touch screen isdetermined at the lower resolution (4, 3), and the switch 576 formultiplexer 566 and corresponding switch for multiplexer 555 (not shown)have been closed. That is, the first scan at the lower resolution candetermine if a touch has occurred and its proximity, that is within thematrix at (4, 3) and the second scan can determine that its location is(11, 14) of the higher resolution. That is, when a touch is detected ata sensor segment (4, 3), a second scan is processed within a particularproximity to the detected touch, but this time, the individual signalsof the sensor segment subsections are not combined to form a singletransmission channel output, the signals of scan lines 568-A, 568-B,568-C and 568-D for vertical position and 580-A, 580-B, 580-C and 580-Dfor horizontal position are individually processed to determine that thetouch was at (11, 14). Put another way, using two scans, the first anormal scan, and the second a higher resolution scan, the disclosedtouch screen and methods zoom in on the touched area (4, 3) and scanswith a higher resolution only where it is needed, in this case,determining that the touch is at the (11, 14) position. Beneficially,many disadvantages of increasing the resolution may be avoided by thedisclosed touch screen and disclosed methods.

Also shown in the embodiment illustrated by FIG. 5, touch screen 530includes sixteen scan lines in the vertical direction 542 grouped intogroups of scan lines so that their signals can be combined by amultiplexers 550, 552, 554 and 556, respectively. As mentioned above,varying levels of resolution may be provided by the same touch screen.Various levels of resolution by the same touch screen may be provided byfurther multiplexing the multiplexed scan lines. For example, the fouroutput transmission channels 551, 553, 555 and 557 of multiplexers 550,552, 554 and 556 may be input to multiplexers 557 and 559 having outputlines (transmission channels) 567 and 569 in the vertical direction 546that are truncated by arrows to indicate that their circuitry (notshown) is coupled to the controller 580. It is understood that anynumber of resolution levels is within the scope of this discussion.Moreover, particular portions of the touch screen may have differentresolution capability that other portions of the touch screen. Forexample, the center of the touch screen may be capable of a higherresolution that the outer portions of the touch screen.

A process for determining which resolution is an appropriate resolutionmay be determined depending upon the application running, on forexample, a mobile communication device. For one application, a lowerresolution may be preferable so that the application runs as fast aspossible. In another application, a higher resolution may be preferableso that a finger writing input recognition application can be effective.In another application, an even higher resolution may be desirable, forexample, so that a stylus writing input recognition application can beeffective. In one embodiment, there may be a plurality of differentresolutions available on a touch screen. For example, three differentresolutions may be available on a touch screen as demonstrated in FIG. 5where output lines 551, 553, 555 and 557 of multiplexers 550, 552, 554and 556 are further multiplexed by multiplexers 557 and 558. Where atraditional sensor segment is replaced by a plurality of sensor segmentsubsections, the sensor subsections can in turn be replaced by evenfiner subsections that operate in the manner that has been describedabove. It is understood that any number of scan lines can bemultiplexed, and any number of multiplexing layers is within the scopeof this discussion.

FIG. 6 is a flow chart illustrating a plurality of embodiments ofmethods of disclosed touch screens. An electronic device such a mobilecommunication device may have many different application stored in itsmemory or in another location. Certain applications may involvehandwriting recognition. As mentioned, varying degrees of resolution maybe desirable depending upon the application. In one embodiment of amethod of the disclosed touch screen, an electronic device may determine681 the application to be run and determine 682 the preferredresolution. If a lower resolution is preferable, then a normal scan caninclude scanning 683 only the first portion of the scan lines that formthe transmission channels to the controller 580 (see FIG. 5).

In the event that a higher resolution is desirable, then a normal scancan occur where the first portion of the scan lines are scanned 684,that is, those receiving the multiplexed signals of a plurality ofsensor segment subsections (see FIG. 5). The proximity of a touch may bedetermined 685 within the area of, for example, a four-by-four matrix ofsensor segment subsections. A second scan may take place 687 todetermine more precisely where within the four-by-four matrix of sensorsegment subsections the touch occurred. Using two scans, the first anormal scan, and the second a higher resolution scan, the disclosedtouch screen and methods zoom in on the touched area and scans with ahigher resolution only where it is needed. In the event that touchscreen has even finer resolution available, in that the subsectionsdepicted in FIG. 5 have subsections, another scan 688 including a thirdportion of scan lines for higher resolution may provide 689 a moreprecise location of the detected touch. Output, such as indicia on thetouch screen may be provided 690, for example to a handwritingrecognition application.

In any event, output may be provided 691. The process may repeat itself,scanning 692 the first portion of the scan lines, providing a normalscan as described above. The proximity of a touch may be determined 693within the area of, for example, a different four-by-four matrix ofsensor segment subsections than previously described. A third scan maytake place 694 to determine more precisely where within the differentfour-by-four matrix of sensor segment subsections the touch occurred.Again, using two scans, the first a normal scan, and the second a higherresolution scan, the disclosed touch screen and methods zoom in on thetouched area to determine 695 the second input location, scanning with ahigher resolution only where it is needed. Appropriate output may beprovided 696.

This disclosure is intended to explain how to fashion and use variousembodiments in accordance with the technology rather than to limit thetrue, intended, and fair scope and spirit thereof. The foregoingdescription is not intended to be exhaustive or to be limited to theprecise forms disclosed. Modifications or variations are possible inlight of the above teachings. The embodiment(s) was chosen and describedto provide the best illustration of the principle of the describedtechnology and its practical application, and to enable one of ordinaryskill in the art to utilize the technology in various embodiments andwith various modifications as are suited to the particular usecontemplated. All such modifications and variations are within the scopeof the invention as determined by the appended claims, as may be amendedduring the pendency of this application for patent, and all equivalentsthereof, when interpreted in accordance with the breadth to which theyare fairly, legally and equitably entitled.

1. A touch screen, comprising: a first plurality of sensor segmentscoupled to first scan lines; and a second plurality of sensor segmentsbeing subsections of one of the first plurality of sensor segments, thesecond plurality of sensor segments including second scan lines that arebundled by a multiplexer configured to aggregate output of the secondplurality of sensor segments into a single transmission channel of afirst scan line.
 2. The touch screen of claim 1 wherein the multiplexeris configured to process signals of the second scan lines individually.3. The touch screen of claim 2, wherein the first scan lines and thesecond scan lines are configured to be in communication with acontroller; wherein the controller is configured to drive a scan of thefirst scan lines to determine receipt of an input to one of the firstplurality of sensor segments; and wherein the controller is configuredto drive a scan of the second scan lines individually when input to theone of the first plurality of sensor segments is determined.
 4. Thetouch screen of claim 3, wherein the first scan lines and the secondscan lines are configured to be in communication with a controller; andwherein the controller is in communication with a memory configured tostore a plurality of applications, wherein the controller is configuredto selectively drive scans of the second scan lines depending upon whichof the plurality of applications is processed by the controller.
 5. Thetouch screen of claim 1 wherein the second plurality of sensor segmentsinclude between four and sixteen subsections.
 6. The touch screen ofclaim 1 wherein the second plurality of sensor segments include betweensixteen and one hundred subsections.
 7. The touch screen of claim 1further comprising: a third plurality of sensor segments beingsubsections of one of the second plurality of sensor segments, the thirdplurality of sensor segments including third scan lines that are bundledby a multiplexer configured to aggregate output of the third pluralityof sensor segments into a single transmission channel of a second scanline.
 8. The touch screen of claim 1 wherein the sensor segments are ofa diamond shape.
 9. The touch screen of claim 1 wherein the touch screenis a display device of a mobile communication device.
 10. A method of atouch screen having a first plurality of segments having scan lines, anda second plurality of segments having scan lines, wherein the secondplurality of segments are subsections of the first plurality ofsegments, comprising: scanning a first portion of the scan lines todetermine input to the touch screen at a detected input location; andscanning a second portion of the scan lines proximal to the detectedinput location.
 11. A method of claim 10 further comprising: displayingoutput on the touch screen proximal to the detected input location. 12.The method of claim 10, further comprising: scanning a first portion ofthe scan lines to determine input to the touch screen at a seconddetected input location; and scanning a third portion of the scan linesproximal to the second detected input location.
 13. The method of claim10 wherein the touch screen is incorporated in a device configured toexecute applications, the method further comprising: determining theapplication of the device; and scanning only the first portion of thescan lines depending on the application.
 14. A method of a touch screenhaving a plurality of sensor segments coupled to scan lines andsubsections of the pluralities of sensor segments coupled to scan lines,the method comprising: scanning scan lines of the plurality of sensorsegments to determine input to the touch screen at a particular sensorsegment; and scanning scan lines of the subsections of the particularsensor segment when input to the touch screen is determined.
 15. Amethod of claim 14 further comprising: displaying output on the touchscreen proximal a location where input to the touch screen has beendetermined.
 16. The method of claim 14 wherein the subsections of thepluralities of sensor segments includes further subsections coupled toscan lines, the method comprising: scanning the scan lines of thefurther subsections when input to the touch screen is determined. 17.The method of claim 14, further comprising: scanning scan lines todetermine input to the touch screen at another sensor segment; andscanning scan lines of the subsections of the another sensor segmentwhen input to the touch screen is determined.
 18. The method of claim 14wherein the touch screen is incorporated in a device configured toexecute applications, the method further comprising: determining theapplication of the device; and scanning only the scan lines of theplurality of sensor segments.